It is known to use a device lock state, such as a screensaver state, in electronic devices, such as mobile stations and PDA (Personal Digital Assistant) devices, to prevent the operation of the device when it is subjected to unintentional keystrokes for instance during transport or inadvertently by the user. The device lock state can be activated for instance by depressing a given key or given keys on the keypad or by selecting said function by the menus of the device. It is also common that, when not used for a given period of time, the device automatically enters the lock state. A special password can be taken into use to prevent unauthorized use of the device, and the user has to input it by means of the keypad, for example, to deactivate the lock state. Separate keys or key cards, for example, for opening locks are also required for access to locked premises, such as homes or offices. For security reasons, it is increasingly more common to lock doors and gates to backyards, residential areas or office buildings.
The drawback in prior art solutions is the difficulty to remember special passwords. If, again, no password is required to deactivate a lock state, the device may be subjected to unauthorized use or be activated by mistake during transport, for example. Passwords may also be mislaid, causing significant economic damage to the user of the device. The use of electronic key codes is also inconvenient. It is difficult to remember key codes and their activation requires special measures. The keys may also easily be mislaid, in which case the locks would have to be changed.